BioMedical Admissions Test (BMAT) Practice Test 2026 - Free BMAT Practice Questions and Study Guide

The formula moles = mass/Mr is accurate because it directly relates the amount of a substance to its mass and its molar mass (Mr). In this context, "mass" refers to the mass of the substance in grams, and "Mr" is the molar mass, which is expressed in grams per mole (g/mol). This relationship is vital in stoichiometry, where understanding the number of moles of reactants and products is essential for predicting the outcomes of chemical reactions.

In practical terms, determining the number of moles using this formula allows chemists to quantitate how much of a substance is present based on its mass. Molar mass gives an indication of how much one mole of that substance weighs, making it straightforward to compute how many moles are present when you know the total mass of the substance you have. This fundamental concept is crucial for various calculations throughout chemistry, including reaction stoichiometry and concentration determinations.

The other options provided do not accurately represent the formula for calculating the number of moles.